The man who will tell us who won the postal survey

Australian Statistician David Kalisch ahead of the postal survey announcement. Photo: Andrew Meares

He's set to be the Juan Antonio Samaranch of the same-sex marriage postal survey. But chances are, you've never heard of David Kalisch.

Come Wednesday at 10am, all eyes will be on the economist who has made his career in the public service. As the head of the Australian Bureau of Statistics, Kalisch has the job of announcing the highly anticipated results of the same-sex marriage postal survey.

He promises not to make people wait ages for the punchline, Rob Oakeshott-style.

"We are working on a relatively short and succinct speech," he says.

At this stage, Kalisch does not know what he will be announcing to Australia. While the ABS began processing responses in September, it will not finalise the results until early next week. Even then, only a handful of officials working on the data will know which side has won before Wednesday morning.

Shortly before the public announcement, Kalisch will brief Finance Minister Mathias Cormann. Representatives of the "yes" and "no" camps will also get a small head start on the results, but will be in a lock up (similar to the one on budget day) and not be able to comment publicly until after the ABS press conference.

Kalisch learned the ABS would be surveying all Australian voters on same-sex marriage a day before the government told the rest of the country of the plan. The Australian statistician was on his way back to Canberra from a business trip in Launceston when he got a call saying Treasurer Scott Morrison wanted a word.

Back in August, the political debate had been focused on whether or not the Australian Electoral Commission could legally be tasked with running a plebiscite without Parliament's approval. When the Senate twice rejected the government's plan, the Coalition turned to the ABS to run a survey instead.

While the news stunned political watchers, Kalisch says the ABS took it in its stride.

"In terms of the ABS then being asked to undertake a survey, that wasn't a surprise to us in that sense, because that's what the ABS does."

Indeed, the bureau is very clear that it is conducting a survey not a plebiscite.

At the last count, almost 80 per cent of eligible voters had returned their survey forms. Photo: AAP

"We have a swear jar here," Kalisch explains. "If anyone calls it a ballot or a vote, it's a dollar in the swear jar," (apparently there will enough for a modest donation to charity, but not enough to fund the Christmas party).

While the ABS surveys the entire country every five years with the census, Kalisch says conducting the marriage law survey within 100 days has been a "really challenging task". The census may entail more questions but it enjoys a much longer lead time: the ABS starts preparing for the next census before the preceding one has finished.

The stakes are also sky high. Not only is the survey at the centre of a heated and emotional debate, it comes barely a year after the ABS's widely publicised "#censusfail", when the ABS had to shut down the census website on census night.

"There were some things that we did that weren't good enough," Kalisch says.

Lead contractors IBM covered the costs of the outage and the census response rate ended up at around 95 per cent (slightly less than previous years), but the ABS took a public confidence hit all the same.

In the month after the same-sex marriage survey was announced, staff met twice a day, seven days a week to get plans in place. This included testing the question on focus groups to make sure it was easy to understand and finding contractors to print the millions of forms. Kalisch stresses the ABS has also taken extra steps around cyber security. The Prime Minister's cyber security adviser Alastair MacGibbon and the Australian Signals Directorate "were engaged at the get go".

While critics predicted a postal vote would be plagued by interference and low-participation, so far, the process has gone relatively smoothly. There have been some reports of dumped ballots, but the ABS says it has replaced these. The high response rate - at nearly 80 per cent with a week to go - has also given the ABS a sense its preparations have worked.

The ABS didn't initially plan to release information on participation during the campaign, but was encouraged to do so as millions of forms started coming back, almost as soon as voting opened.

"To let not just the community know, but the campaigns know ... And I suppose our hope was that that would moderate some of the heat that might have been in the campaigning," Kalisch explains.

Kalisch has built his career around data, at the OECD, Productivity Commission and Australian Institute of Health and Welfare. He is passionate about using statistics to "make a difference" in the choices that governments, businesses and households make.

"Evidence is better than prejudice or anecdote, any time."

Asked if he would like to see the ABS used to survey Australians in a similar way to the postal vote again, Kalisch replies: "I hope this doesn't become a regular feature in terms of the timing. But certainly what the ABS does is we do surveys and we produce statistics."